The invention concerns a test carrier for the analytical determination of components of body fluids from an amount of sample. The test carrier contains a carrier layer and several test layers arranged thereupon in such a manner that an exchange of fluid is possible between them. The layers incorporate an application zone for the application of a sample of the body fluid, a detection zone containing at least one detection layer for the production of a detectable signal characteristic for the analytical determination and an absorption zone of an absorbent material arranged in sequence substantially next to one another on the carrier layer.
For the qualitative and quantitative analytical determination of components of body fluids, especially of blood, in recent times so-called carrier bound tests are increasingly employed. In these, reagents are embedded in layers of a solid test carrier which is brought into contact with the sample. The reaction of sample and reagents leads to a detectable signal, especially a color change, which can be evaluated visually or with the help of an apparatus, usually a reflection-photometer.
Test carriers are frequently constructed as test strips which consist essentially of a longitudinal carrier layer of synthetic resin material and test fields applied thereto. However, test carriers are also known which are formed as quadratic or rectangular platelets.
Carrier-bound tests are characterized especially by the simplicity of their handling. The result of this is that such tests are also being used more and more by lay persons or for use in at home diagnosis where specialized laboratory personnel are not always available.
Previously known test carriers work without sample dosing, and reproducible impregnation of the reaction layer of the test carrier is achieved by first applying the sample in excess and the sample excess is then wiped off or washed off. Handling of the test carrier is thereby made difficult. In particular, however, wiping off or washing off leads to user-dependent sources of error if it is not carried out completely correctly.
From German Patent Specification No. 34 45 816, a strip-shaped test carrier is known in which, on a carrier layer, several absorbent test layers are present arranged next to one another in such a, manner that they are in absorbent contact with one another via their edges. This known test carrier is intended for immunological tests in which, apart from the sample, an elution agent is employed. The elution agent is applied to one end of the overall longitudinal test carrier and migrates through the test layers in the form of a liquid stream which comes to a stop at the other end of the test carrier. The sample is applied either at the same place as the elution agent or in the middle region of the carrier. This patent application does not address the problem of the dosing of the sample in a reaction layer of the test carrier. Dosing plays no part in the use of the carrier because the sample is introduced in precise dosaging into the elution agent stream and the elution agent is introduced until it completely fills the test carrier.